Effects of deposition temperature on the properties of hermetically carbon-coated optical fibers prepared by thermal chemical vapor deposition

The effects of deposition temperature on the properties of hermetically carbon-coated optical fibers are investigated. Hermetically carbon-coated optical fibers are prepared by thermal chemical vapor deposition using methane as the precursor gas. The deposition temperatures are 900, 925, 950, 975 and 1000 °C. The deposition rate, microstructure, electrical resistivity and Young's modulus of the carbon films are measured. The water-repellency and low-temperature surface morphology of carbon-coated optical fibers are elucidated. The results indicate that the deposition rate and electrical resistivity of the carbon films increase with the deposition temperature, while the degree of ordering, the nano-crystallite size and the Young's modulus of the carbon film decrease. Additionally, the water-repellency and low-temperature surface morphology of the carbon films show that the carbon film that is deposited at a temperature of 950 °C is the best for use in hermetical optical fiber coating.